A simple, robust, plasma-based, variable pulse-length electron beam source that produces 10's nsec to 100's msec pulses is reported. Different pulse-lengths were achieved through utilization of different modes of operation of the back-lighted thyratron or pseudospark, which were controlled by external circuitry. Three distinct modes are identified: a transient hollow cathode discharge, a quasi steady-state hollow cathode discharge and a super-emissive cathode mode. During the transient hollow cathode discharge an electron beam with duration - 50 nsec, current - 60 A, normalized brightness - 4*101Ã‚Â° A/m2rad2 was measured. The electron beam during operation in the super-emissive mode has beam current ---100 A and duration - 1 Ã‚Âµsec. The quasi steady state hollow cathode discharge produces an electron beam with energy -- 100's eV and duration --100's msec. Several applications, including the electron beam ion trap, are to be discussed.